1. Field of the Invention
The invention relates to a block brake for rail vehicles in which a brake linkage is acted on by a brake cylinder and acts radially on at least one wheel set of a bogie, truck or running gear of the rail vehicle through brake blocks which include brake block shoes and brake block shoe inserts.
In practice, brake blocks for rail vehicles are known, in particular in the field of freight traffic, through which the entire braking of the rail vehicle takes place up to a maximum permissible speed of 120 km/h. In those known block brakes, the brake blocks which include brake block shoes and brake block shoe inserts act directly on the running tread of the tire of the wheel of the wheel set. The brake blocks are attached on a brake beam which is usually configured in the shape of a triangle (brake triangle). The brake block shoes with the brake beam are mounted in an articulated fashion in the rail vehicle or in the bogie of the rail vehicle on its frame and are acted on by a brake cylinder through a brake pull rod with the intermediate connection of the center brake linkage and possible connecting levers between the brake beams.
Such a block brake which is described above fulfills its function satisfactorily up to the aforesaid speed with loads of up to 22.5 t per axle, which is customary in freight traffic, and includes simple components which are economical to manufacture and can be serviced with a low degree of expenditure. However, it has proven a disadvantage that the braking heat which is produced during braking leads to damage to the tire of the wheel and to the running tread.
The consequence thereof is a rough and bumpy running tread and possibly even the formation of fractures in the running tread. As a result of the mechanical effect of the brake blocks on the running tread, corrugations are additionally formed on the running tread. As a result of those changes to the running tread of the tire of the wheel, a very loud wheel noise is produced. When the tire of the wheel is damaged as a result of the formation of fractures, the wheel set must be replaced.
It is also a disadvantage that in order to limit the braking heat produced during braking, the permissible braking capacities are far below the range which would be theoretically achievable.